Milking short-term disability benefits...

A close relative of mine went on short-term disability leave back in September right before having early-stage breast cancer surgery and has been receiving short-term disability payments from her employer's insurance company ever since. Following surgery and subsequent radiation (she didn't need chemo), more and more "stuff" started appearing at her house that she'd been buying with the insurance money--new clothes, a new sofa, she's talking about getting a treadmill, etc.--and spending hours online looking up genealogy-related stuff, which is a big hobby of hers. She's also taken a number of trips to see relatives around the state and has gone with them on hobby-oriented excursions for several days at a time (some of the relatives are self-employed while others are retired) and apparently having a grand old time. Meanwhile she's had no medical treatments in nearly two months--she finished radiation in January--but she says she still doesn't feel well enough to go back to work, and oh yeah, she also mentioned out loud on at least one occasion that she's making more money from short-term disability than she does from her job. But she feels really lousy and can't go back to work because she's not ready, yadda yadda yadda, but you wouldn't know it from the way she's been acting and the way she's been spending money on things she doesn't need to live.

I'm waiting to hear back from her insurance company on an anonymous call I placed to their fraud hotline, but it got me to wondering...I and many other relatives are seeing her do all of these things, but she's apparently still giving her doctor this line that she's not ready to go back to work, etc., and besides the fact that she's stealing from the system, it's really creating major tensions within the family. So what I'm asking is, once I give the insurance company the details of what I know and what I've observed, how can it be proven that she's milking the system and what can be done to stop her? In the back of my mind I'm thinking it could even get her arrested if this sort of fraud is deemed serious enough, but not having dealt with anything like this before, I'm not sure how this plays out. Anyone have any insight on the process in reporting insurance/disability fraud and how insurance investigators go about proving something like this? I realize people can't give legal advice on here, but I'm just trying to understand how the system works and anything else that might be a consideration.